Summary

The new surgical technique for acromioclavicular (AC) dislocation, which reconstructs the superior half of the AC ligament complex using dermal allograft, showed both good stabilities of posterior translation and rotation.

Abstract

Background

The optimal surgical procedure for acromioclavicular (AC) dislocation is still debated. Persistent posterior instability of the AC joint after surgery has been reported to decrease clinical outcomes. We have a developed a new surgical technique for treatment of AC dislocations (ACLC-patch technique) which reconstructs the superior half of the AC ligament complex using dermal allograft to restore the posterior translational and rotational stability.

Purpose

To biomechanically evaluate the posterior translational and rotational stability of an ACLC-patch technique in direct comparison to three suture brace techniques constructs (oblique brace, anterior brace, and x-frame brace).

Methods

Twenty-eight fresh-frozen cadaveric shoulders were randomly assigned to 1 of 4 AC surgical techniques: ACLC-patch, oblique brace, anterior brace, and x-frame brace. The force and torque to achieve 10 mm of posterior translation and 20° of posterior rotation were recorded in following conditions: (1) intact, (2) dissected ACLC, (3) ACLC-patch/brace repair with intact CC ligaments, (4) ACLC-patch/brace repair with dissected CC ligaments, and (5) ACLC-patch/brace repair with CC ligaments repair.

Results

Translational testing: Dissection of the ACLC reduced the resistance to 10 mm of posterior translation to 16.7% of the intact state. With the native CC ligaments intact, the ACLC-patch (59.1%), oblique brace (54.1%), and anterior brace (60.7%) provided significantly greater stability than the x-frame brace (33.2%; P < .001, P = .008, P< .001, respectively). After dissection of the CC ligaments and subsequent CC repair, the ACLC-patch (65.6%), oblique brace (58.4%), and anterior-brace (61.2%) continued to have significantly higher resistance to posterior translation than the x-frame brace (35.1%, P < .001, P = .003, P < .001, respectively).
Rotational testing: Dissection of the ACLC decreased the resistance to 20° of posterior rotation to 5.4% of the intact state. With the native CC ligaments intact, the ACLC-patch (77.1%) restored more stability than the oblique (35.3%), anterior (48.5%), and x-frame (23.0%) brace repairs (P < .001, P = .002, P < .001, respectively). After dissection of the CC ligaments and subsequent CC repair, the ACLC-patch (41.0%) continued to have improved stability compared to the oblique (16.0%), anterior (14.0%), and x-frame (12.7%) brace repairs (P = .006, P = .003, P = .002, respectively).

Conclusion

The ACLC-patch technique restored a greater degree of posterior rotational AC stability than three brace techniques, and restored posterior translational AC stability to a similar extent as the oblique and anterior brace techniques.